[burtomr]

I'm erasing the previous comments about the hifiman whatever model being better than one of the AK devices...

 
                      

 

[the8o88y]

  I don't think the USB cable for the HM-901 features audio output - or am I wrong? This one says it's only for data exchange: https://head-direct.com/Products/?act=detail&id=166
There is a S/PDIF output (and input) cable that will feed an external DAC: https://head-direct.com/Products/?act=detail&id=170
 

 
That's correct, I should have read up on that a bit more. I was used to connecting my iPod via usb to my stereo's 24-bit DAC. That being the case, for my car stereo system, would the SQ be better from the 901 headphone out with an aux cord?

 

[ph58]

Hi , guys do you see this ? :    http://www.head-fi.org/t/709479/multi-review-hifiman-hm901-fiio-x5-sony-zx1-hisound-studio-3rd-anv-iphone-4

Listening Tests​

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 ​

 ​

 ​

I chose about 100 of my favorite songs to listen with. I tried to make sure they were of the best mastering quality I could find. The songs are all in 320 kbps MP3 format. Some were in lossless FLAC, but I heard no difference between those and the resulting MP3 conversions from dbpoweramp. As such, I'm going with the MP3 files. I won't go through and list the tracks, but I may mention a few specifics in head to head comparisons.
 

 ​

I've volume matched all players as closely as I could, as volume is critical when comparing DAPs where the differences are FAR less pronounced than with headphones. The process of comparing involves me loading identical files on the players, then listening closely to small sections of the track. I have an A/B method that somewhat approximates the scientific method. If I think I hear something, I'll go back multiple times to ensure that it wasn't a fluke before noting it down.
 
This review will focus primarily on sound quality, but I'll probably have blurbs about the players when certain things stand out to me.
 
 
When listening, I'll be using my iPhone 4 as the baseline. Again, volume levels will be carefully matched by ear. 
 
 
 
 
 
 
 

The Players​

 
 

 ​

Hifiman HM901 (IEM Card)​

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 ​

 ​

 
Long considered as the main sheriff in town, the HM901 offers tremendous versatility with varying amp modules, including a balanced mode. The UI is also quite acceptable, though I've encountered a few freezes requiring me to reset the player by removing the battery.
 
The very first track I listened to with the HM-901 was Ben Howard's Everything, a favorite of mine. Switching back and forth with the iP4, the most noticeable thing is that the iP4 has slightly more forward upper mids, giving slightly better clarity and attack to notes. In exchange, the the HM-901 seems to have slightly more space between cues, as well maybe a wider stage. Note how I emphasized the "slightly"s.
 
So far, the iPhone appears to be keeping up with the grand daddy HM901...strange. As I go through more test tracks, these differences hold up. I arrive at Quarter Chicken Dark by Yo-Yo Ma on the Goat Rodeo Sessions album. I love this particular track because of the mixing of the highly textured cello mixed with the sweetness of the violin. I started with the iPhone 4, taking notes between in the area between 1:35 and 2:15, then switched to the HM-901 to compare how it presented bass texturing since it's been lauded in that area. Interestingly, The HM901 seems to present no advantage over the iPhone 4 in that regard, and the iP4 seems to have slightly sweeter and better separated violins.

 

[Mimouille]

  Hi , guys do you see this ? :    http://www.head-fi.org/t/709479/multi-review-hifiman-hm901-fiio-x5-sony-zx1-hisound-studio-3rd-anv-iphone-4

Listening Tests​

 ​

 ​

 ​

 ​

I chose about 100 of my favorite songs to listen with. I tried to make sure they were of the best mastering quality I could find. The songs are all in 320 kbps MP3 format. Some were in lossless FLAC, but I heard no difference between those and the resulting MP3 conversions from dbpoweramp. As such, I'm going with the MP3 files. I won't go through and list the tracks, but I may mention a few specifics in head to head comparisons.
 

 ​

I've volume matched all players as closely as I could, as volume is critical when comparing DAPs where the differences are FAR less pronounced than with headphones. The process of comparing involves me loading identical files on the players, then listening closely to small sections of the track. I have an A/B method that somewhat approximates the scientific method. If I think I hear something, I'll go back multiple times to ensure that it wasn't a fluke before noting it down.
 
This review will focus primarily on sound quality, but I'll probably have blurbs about the players when certain things stand out to me.
 
 
When listening, I'll be using my iPhone 4 as the baseline. Again, volume levels will be carefully matched by ear. 
 
 
 
 
 
 
 

The Players​

 
 

 ​

Hifiman HM901 (IEM Card)​

 ​

 ​

 ​

 
Long considered as the main sheriff in town, the HM901 offers tremendous versatility with varying amp modules, including a balanced mode. The UI is also quite acceptable, though I've encountered a few freezes requiring me to reset the player by removing the battery.
 
The very first track I listened to with the HM-901 was Ben Howard's Everything, a favorite of mine. Switching back and forth with the iP4, the most noticeable thing is that the iP4 has slightly more forward upper mids, giving slightly better clarity and attack to notes. In exchange, the the HM-901 seems to have slightly more space between cues, as well maybe a wider stage. Note how I emphasized the "slightly"s.
 
So far, the iPhone appears to be keeping up with the grand daddy HM901...strange. As I go through more test tracks, these differences hold up. I arrive at Quarter Chicken Dark by Yo-Yo Ma on the Goat Rodeo Sessions album. I love this particular track because of the mixing of the highly textured cello mixed with the sweetness of the violin. I started with the iPhone 4, taking notes between in the area between 1:35 and 2:15, then switched to the HM-901 to compare how it presented bass texturing since it's been lauded in that area. Interestingly, The HM901 seems to present no advantage over the iPhone 4 in that regard, and the iP4 seems to have slightly sweeter and better separated violins.

I hear things very differently than Eke, and his reviews always end up supporting his way of thinking...quite miraculously. I personally find idevices quite behind the 901, even with iems. Listen for yourself and judge

 

[ph58]

i can not believe that IP4 is better than the HM901 , my HM901+Discrete card sound PHENOMENAL ! It is by far the best of all my dap

 

[warrior1975]

I enjoy Eke and chatting with him but this review I can not even remotely come close to agreeing with. I kid you not, I have the worst ears here in head-fi, so bad that the ak100ii sounds identical to my AK240. No joke. I can easily pick out my ipod 5g touch between the ak100ii. I heard an audible difference between my X3 and X1, and obviously the Fiio and AK devices. I'd have an extremely hard time picking between my 3 goto IEMS, Shure Se846, Tralucent Ref 1, a d ASG -g2. My ears suck. I can hear the difference between those daps.

Best thing, as always on Head-Fi, take things with a grain of salt and listen for yourself. If you are loving your hifiman, than continue to love it in peace.

 

[MikePortnoy]

I agree with Mim regarding sq of 901. I had a chance to make a comparison between rwak240 and 901 miniboxed. 901 is better on sq wise. 901 has a some kind of more technical presentation, while 240 is a more mellow sounding dap compared to 901.

 

[warrior1975]

Stop this immediately!!!! On a serious note, I really would like one of these... Just not sure if I'd like the experience. If I see one for a decent deal, I may grab one...

 

[lee730]

I'm apt to believe what mimouille says. While my iphone4 sounded not half bad there is much better to be had for DAPs. Just depends if it is worth it to you or if you can hear those differences for yourself. For those who can't. Well good for you. Save your money. Doesn't mean others can't hear things that you can't though.

 

[warrior1975]

Unfortunately I believe Mim... Wish I didn't though!!

 

[wlz12]

  The 901s was announced a while ago w/ some cosmetic changes plus better power management. But later on Hifiman decided to give it a full refreshed design w/ probably some internal change/upgrade too. Don't think it's gonna be available anytime soon given our experiences w/ previous Hifiman DAPs. I'd just get a 901 first if I were you, and upgrade to the 901s if it's MUCH better than the 901. Hifiman will upgrade for us 901 owners w/ certain amount of cost only. 

Sorry I missed your comment, great advice. I just used my "toy funds" for other reasons, i will probably get it by the end of the year, or mid January the latest. Thanks for the heads up. Can't wait to get my hands om this DAP.
 
I heard there are multiple versions available in the market, and that the early models were less sturdy. Can anyone help me with the productions dates? Which ones are best

 

[Mimouille]

Believing Mim is not healthy financially.

 

[fengwei007]

  Sorry I missed your comment, great advice. I just used my "toy funds" for other reasons, i will probably get it by the end of the year, or mid January the latest. Thanks for the heads up. Can't wait to get my hands om this DAP.
 
I heard there are multiple versions available in the market, and that the early models were less sturdy. Can anyone help me with the productions dates? Which ones are best

Yes, the quality of HM901 has been improving since it's launched a year and half ago. The very early batch (before mid 2013) has some problem w/ the center wheel which comes out easily. There are some problems w/ the battery latch and back cover latch too. These problems have been fixed (almost) in the subsequent batches. But these are not really big deals.
 
Other than these, the battery, the charger and even the volume knob changed a bit here and there, all for better.
 
Actually most problems were due to firmware issues, which made quite some users not very happy. The firmware has improved quite a lot ever since, especially the latest TaiJi V2 firmware. It's been very stable to me so far.
 
There are some further improvements in the latest batch (the current new fresh stocks), which Hifiman calls it as HM901a, and this will be the final version before the HM901s (if the name doesn't change) comes out. I just got the latest batch last week, the center wheel is much improved over the one I bought half a year ago. It's smoother, it's sunk in a bit more than the previous version, as you can see from the following photos:
 

 

 

 

 

 

I'm on the beta version v2.002 firmware, really love the new 901. Now let's wait and see how much better the HM901s would be

 

[ph58]

Hi Feng which one is from the latest batch , the right or the left one ? Thanks

 

[KT66]

what's the difference between 2.001 and 2.002?
with 2.001 I can't really fault mine, so interested to hear of any changes.